György L, Dóda M
Arch Int Pharmacodyn Ther. 1985 May;275(1):22-32.
Responses to i.v. administration of dopamine, apomorphine, piribedil and bromocriptine were investigated in the feline mesenteric vascular bed. Dopamine increases the mesenterial flow in doses of 0.3 to 30 micrograms/kg; its effect can be inhibited by 1 to 3 mg/kg of sulpiride. Apomorphine and piribedil also increased the blood flow, but only in 20 to 200 times higher doses; they show a tachyphylaxis phenomenon and their maximal activity is 32 and 59 per cent, respectively, that of dopamine. Apomorphine is a partial agonist of dopamine and can inhibit the activity of the transmitter amine. Bromocriptine has no activity on the feline mesenterial flow. The postsynaptic dopamine receptors of the cat can be characterized by the following: strong efficacy of dopamine and lower ones of apomorphine, piribedil and of sulpiride. The presynaptic dopamine receptors are involved mostly in the hypotension, they are activated by low doses of apomorphine, and piribedil and by higher doses of dopamine; sulpiride reacts with these receptors in much lower doses than with the postsynaptic ones.
在猫肠系膜血管床中研究了静脉注射多巴胺、阿扑吗啡、匹罗卡品和溴隐亭的反应。多巴胺以0.3至30微克/千克的剂量增加肠系膜血流量；其作用可被1至3毫克/千克的舒必利抑制。阿扑吗啡和匹罗卡品也增加血流量，但剂量要高20至200倍；它们表现出快速耐受现象，其最大活性分别为多巴胺的32%和59%。阿扑吗啡是多巴胺的部分激动剂，可抑制递质胺的活性。溴隐亭对猫肠系膜血流量无活性。猫的突触后多巴胺受体具有以下特征：多巴胺的效力强，而阿扑吗啡、匹罗卡品和舒必利的效力较低。突触前多巴胺受体主要参与低血压，它们被低剂量的阿扑吗啡、匹罗卡品和高剂量的多巴胺激活；舒必利与这些受体反应的剂量远低于与突触后受体反应的剂量。
